It is well known that most internal combusion engines have a cooling system in which excess heat generated during the operation of the engine is removed by circulating a coolant fluid through the cooling system of such an engine. Generally, water containing various materials is the coolant fluid used for this purpose.
A suitable coolant fluid must meet the following basic requirements:
1. Provide adequate heat transfer.
2. Provide a corrosion-resistant environment within the cooling system.
3. Prevent formation of scale or sludge deposits in the cooling system.
4. Be compatible with the cooling system hose and seal materials.
5. Provide adequate freeze protection during cold weather operation.
Oil-based coolants provide several advantages over the conventional aqueous coolants. These advantages include
1. Reduction in expensive engine rebuild due to leakage of coolant into the crankcase;
2. Longer engine life;
3. Eliminate the need for supplemental coolant corrosion inhibitor and expensive filters;
4. Faster engine warm-up; and
5. Increased horsepower output.
Therefore, it is the object of this invention to provide a novel method for cooling an internal combustion engine which comprises circulating within the cooling system of said engine an oleaginous coolant fluid composition.
Another object is to provide a novel cooling system for an internal combustion engine wherein said cooling system contains an oleaginous coolant fluid composition.
These and other objects of the invention are accomplished by providing a method for cooling an internal combustion engine which comprises circulating within the cooling system of said engine an oleaginous coolant fluid composition comprising:
(A) a major amount of a lubricating oil having a kinematic viscosity of from about 3.5 up to about 5 cSt at 100.degree. C. and from about 18 up to about 30 cSt at 40.degree. C.;
(B) a minor amount of a composition selected from the group consisting of
(1) one or more basic metal salts of organic acids; PA1 (2) one or more phosphorus containing metal salts; PA1 (3) one or more phenolic antioxidants; PA1 (4) one or more pour point depressants; and mixtures of two or more of (B)(1) through (B)(4).
In another embodiment, the objects of this invention are accomplished by providing a cooling system of an internal combustion engine which contains within said cooling system of said engine the oleaginous coolant fluid composition described hereinabove.